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/******************************************************************************

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 *

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 *  $Id$

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 *

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 *  Copyright (C) 2006  Florian Pose, Ingenieurgemeinschaft IgH

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 *

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 *  This file is part of the IgH EtherCAT Master.

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 *

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 *  The IgH EtherCAT Master is free software; you can redistribute it

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 *  and/or modify it under the terms of the GNU General Public License

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 *  as published by the Free Software Foundation; either version 2 of the

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 *  License, or (at your option) any later version.

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 *

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 *  The IgH EtherCAT Master is distributed in the hope that it will be

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 *  useful, but WITHOUT ANY WARRANTY; without even the implied warranty of

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 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

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 *  GNU General Public License for more details.

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 *

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 *  You should have received a copy of the GNU General Public License

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 *  along with the IgH EtherCAT Master; if not, write to the Free Software

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 *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

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 *

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 *  The right to use EtherCAT Technology is granted and comes free of

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 *  charge under condition of compatibility of product made by

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 *  Licensee. People intending to distribute/sell products based on the

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 *  code, have to sign an agreement to guarantee that products using

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 *  software based on IgH EtherCAT master stay compatible with the actual

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 *  EtherCAT specification (which are released themselves as an open

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 *  standard) as the (only) precondition to have the right to use EtherCAT

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 *  Technology, IP and trade marks.

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 *

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 *****************************************************************************/

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/**

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   \file

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   Ethernet-over-EtherCAT (EoE).

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*/

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/*****************************************************************************/

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#include <linux/netdevice.h>

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#include <linux/etherdevice.h>

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#include "../include/ecrt.h"

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#include "globals.h"

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#include "master.h"

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#include "slave.h"

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#include "mailbox.h"

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#include "ethernet.h"

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/**

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   Defines the debug level of EoE processing

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   0 = No debug messages.

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   1 = Output actions.

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   2 = Output actions and frame data.

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*/

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#define EOE_DEBUG_LEVEL 0

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/*****************************************************************************/

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void ec_eoe_flush(ec_eoe_t *);

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// state functions

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void ec_eoe_state_rx_start(ec_eoe_t *);

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void ec_eoe_state_rx_check(ec_eoe_t *);

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void ec_eoe_state_rx_fetch(ec_eoe_t *);

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void ec_eoe_state_tx_start(ec_eoe_t *);

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void ec_eoe_state_tx_sent(ec_eoe_t *);

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// net_device functions

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int ec_eoedev_open(struct net_device *);

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int ec_eoedev_stop(struct net_device *);

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int ec_eoedev_tx(struct sk_buff *, struct net_device *);

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struct net_device_stats *ec_eoedev_stats(struct net_device *);

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/*****************************************************************************/

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/**

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   EoE constructor.

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   Initializes the EoE handler, creates a net_device and registeres it.

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*/

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int ec_eoe_init(ec_eoe_t *eoe /**< EoE handler */)

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{

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    ec_eoe_t **priv;

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    int result, i;

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    eoe->slave = NULL;

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    ec_datagram_init(&eoe->datagram);

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    eoe->state = ec_eoe_state_rx_start;

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    eoe->opened = 0;

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    eoe->rx_skb = NULL;

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    eoe->rx_expected_fragment = 0;

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    INIT_LIST_HEAD(&eoe->tx_queue);

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    eoe->tx_frame = NULL;

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    eoe->tx_queue_active = 0;

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    eoe->tx_queued_frames = 0;

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    eoe->tx_queue_lock = SPIN_LOCK_UNLOCKED;

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    eoe->tx_frame_number = 0xFF;

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    memset(&eoe->stats, 0, sizeof(struct net_device_stats));

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    if (!(eoe->dev =

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          alloc_netdev(sizeof(ec_eoe_t *), "eoe%d", ether_setup))) {

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        EC_ERR("Unable to allocate net_device for EoE handler!\n");

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        goto out_return;

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    }

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    // initialize net_device

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    eoe->dev->open = ec_eoedev_open;

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    eoe->dev->stop = ec_eoedev_stop;

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    eoe->dev->hard_start_xmit = ec_eoedev_tx;

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    eoe->dev->get_stats = ec_eoedev_stats;

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    for (i = 0; i < ETH_ALEN; i++)

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        eoe->dev->dev_addr[i] = i | (i << 4);

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    // initialize private data

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    priv = netdev_priv(eoe->dev);

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    *priv = eoe;

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    // Usually setting the MTU appropriately makes the upper layers

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    // do the frame fragmenting. In some cases this doesn't work

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    // so the MTU is left on the Ethernet standard value and fragmenting

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    // is done "manually".

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#if 0

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    eoe->dev->mtu = slave->sii_rx_mailbox_size - ETH_HLEN - 10;

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#endif

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    // connect the net_device to the kernel

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    if ((result = register_netdev(eoe->dev))) {

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        EC_ERR("Unable to register net_device: error %i\n", result);

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        goto out_free;

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    }

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    // make the last address octet unique

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    eoe->dev->dev_addr[ETH_ALEN - 1] = (uint8_t) eoe->dev->ifindex;

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    return 0;

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 out_free:

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    free_netdev(eoe->dev);

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    eoe->dev = NULL;

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 out_return:

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    return -1;

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}

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/*****************************************************************************/

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/**

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   EoE destructor.

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   Unregisteres the net_device and frees allocated memory.

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*/

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void ec_eoe_clear(ec_eoe_t *eoe /**< EoE handler */)

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{

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    // empty transmit queue

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    ec_eoe_flush(eoe);

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    if (eoe->tx_frame) {

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        dev_kfree_skb(eoe->tx_frame->skb);

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        kfree(eoe->tx_frame);

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    }

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    if (eoe->rx_skb) dev_kfree_skb(eoe->rx_skb);

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    ec_datagram_clear(&eoe->datagram);

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}

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/*****************************************************************************/

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/**

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   Empties the transmit queue.

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*/

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void ec_eoe_flush(ec_eoe_t *eoe /**< EoE handler */)

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{

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    ec_eoe_frame_t *frame, *next;

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    spin_lock_bh(&eoe->tx_queue_lock);

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    list_for_each_entry_safe(frame, next, &eoe->tx_queue, queue) {

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        list_del(&frame->queue);

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        dev_kfree_skb(frame->skb);

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        kfree(frame);

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    }

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    eoe->tx_queued_frames = 0;

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    spin_unlock_bh(&eoe->tx_queue_lock);

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}

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/*****************************************************************************/

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/**

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   Sends a frame or the next fragment.

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*/

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int ec_eoe_send(ec_eoe_t *eoe /**< EoE handler */)

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{

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    size_t remaining_size, current_size, complete_offset;

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    unsigned int last_fragment;

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    uint8_t *data;

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#if EOE_DEBUG_LEVEL > 1

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    unsigned int i;

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#endif

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    remaining_size = eoe->tx_frame->skb->len - eoe->tx_offset;

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    if (remaining_size <= eoe->slave->sii_tx_mailbox_size - 10) {

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        current_size = remaining_size;

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        last_fragment = 1;

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    }

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    else {

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        current_size = ((eoe->slave->sii_tx_mailbox_size - 10) / 32) * 32;

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        last_fragment = 0;

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    }

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    if (eoe->tx_fragment_number) {

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        complete_offset = eoe->tx_offset / 32;

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    }

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    else {

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        complete_offset = remaining_size / 32 + 1;

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    }

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#if EOE_DEBUG_LEVEL > 0

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    EC_DBG("EoE TX sending %sfragment %i with %i octets (%i)."

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           " %i frames queued.\n", last_fragment ? "last " : "",

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           eoe->tx_fragment_number, current_size, complete_offset,

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           eoe->tx_queued_frames);

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#endif

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#if EOE_DEBUG_LEVEL > 1

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    EC_DBG("");

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    for (i = 0; i < current_size; i++) {

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        printk("%02X ", frame->skb->data[eoe->tx_offset + i]);

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        if ((i + 1) % 16 == 0) {

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            printk("\n");

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            EC_DBG("");

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        }

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    }

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    printk("\n");

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#endif

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    if (!(data = ec_slave_mbox_prepare_send(eoe->slave, &eoe->datagram,

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                                            0x02, current_size + 4)))

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        return -1;

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    EC_WRITE_U8 (data,     0x00); // eoe fragment req.

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    EC_WRITE_U8 (data + 1, last_fragment);

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    EC_WRITE_U16(data + 2, ((eoe->tx_fragment_number & 0x3F) |

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                            (complete_offset & 0x3F) << 6 |

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                            (eoe->tx_frame_number & 0x0F) << 12));

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    memcpy(data + 4, eoe->tx_frame->skb->data + eoe->tx_offset, current_size);

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    ec_master_queue_datagram(eoe->slave->master, &eoe->datagram);

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    eoe->tx_offset += current_size;

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    eoe->tx_fragment_number++;

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    return 0;

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}

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/*****************************************************************************/

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/**

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   Runs the EoE state machine.

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*/

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void ec_eoe_run(ec_eoe_t *eoe /**< EoE handler */)

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{

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    if (!eoe->opened) return;

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    // call state function

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    eoe->state(eoe);

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}

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/*****************************************************************************/

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/**

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   Returns the state of the device.

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   \return 1 if the device is "up", 0 if it is "down"

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*/

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unsigned int ec_eoe_active(const ec_eoe_t *eoe /**< EoE handler */)

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{

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    return eoe->slave && eoe->opened;

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}

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/******************************************************************************

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 *  STATE PROCESSING FUNCTIONS

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 *****************************************************************************/

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/**

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   State: RX_START.

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   Starts a new receiving sequence by queueing a datagram that checks the

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   slave's mailbox for a new EoE datagram.

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*/

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void ec_eoe_state_rx_start(ec_eoe_t *eoe /**< EoE handler */)

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{

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    if (!eoe->slave->online || !eoe->slave->master->device->link_state)

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        return;

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   308

    ec_slave_mbox_prepare_check(eoe->slave, &eoe->datagram);

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    ec_master_queue_datagram(eoe->slave->master, &eoe->datagram);

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    eoe->state = ec_eoe_state_rx_check;

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}

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/*****************************************************************************/

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/**

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   State: RX_CHECK.

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   Processes the checking datagram sent in RX_START and issues a receive

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   datagram, if new data is available.

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*/

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void ec_eoe_state_rx_check(ec_eoe_t *eoe /**< EoE handler */)

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{

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        eoe->stats.rx_errors++;

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        eoe->state = ec_eoe_state_tx_start;

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        return;

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    }

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    if (!ec_slave_mbox_check(&eoe->datagram)) {

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        eoe->state = ec_eoe_state_tx_start;

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        return;

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    }

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    ec_slave_mbox_prepare_fetch(eoe->slave, &eoe->datagram);

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    ec_master_queue_datagram(eoe->slave->master, &eoe->datagram);

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    eoe->state = ec_eoe_state_rx_fetch;

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}

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/*****************************************************************************/

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/**

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   State: RX_FETCH.

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   Checks if the requested data of RX_CHECK was received and processes the

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   EoE datagram.

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*/

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void ec_eoe_state_rx_fetch(ec_eoe_t *eoe /**< EoE handler */)

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{

   349

    size_t rec_size, data_size;

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    uint8_t *data, frame_type, last_fragment, time_appended;

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    uint8_t frame_number, fragment_offset, fragment_number;

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    off_t offset;

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        eoe->stats.rx_errors++;

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        eoe->state = ec_eoe_state_tx_start;

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        return;

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    }

   359

   360

    if (!(data = ec_slave_mbox_fetch(eoe->slave, &eoe->datagram,

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                                     0x02, &rec_size))) {

   362

        eoe->stats.rx_errors++;

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        eoe->state = ec_eoe_state_tx_start;

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        return;

   365

    }

   366

   367

    frame_type = EC_READ_U16(data) & 0x000F;

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   370

#if EOE_DEBUG_LEVEL > 0

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        EC_DBG("other frame received.\n");

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#endif

   373

        eoe->stats.rx_dropped++;

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        eoe->state = ec_eoe_state_tx_start;

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    }

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}

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/*****************************************************************************/

   483

   484

/**

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   State: TX START.

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   Starts a new transmit sequence. If no data is available, a new receive

   487

   sequence is started instead.

   488

*/

   489

   490

void ec_eoe_state_tx_start(ec_eoe_t *eoe /**< EoE handler */)